Pictures: "Pancake" Sea Slug Among New Philippines Species

One Swell Shark

Photograph courtesy Stephanie Stone, California Academy of Sciences

A new deep-sea swell shark is one of the hundreds of potentially new species discovered on a recent expedition to the Philippines.

The shark, so named because it can suck in water to swell up and frighten predators, is likely new to science. Other known species of swell shark live elsewhere in the Pacific and Indian Oceans, according to expedition scientists at the California Academy of Sciences.

Biologists spent 42 days on and around Luzon Island (see map), the largest island in the Philippine archipelago, surveying creatures of the land and sea.

"We found new species during nearly every dive and hike as we surveyed the country's reefs, rain forests, and the ocean floor," Terry Gosliner, leader of the 2011 Philippines Biodiversity Expedition, said in a statement.

While many of the species still need to be confirmed as new using microscopes or DNA sequencing, the team is confident that three hundred or so are new to science.

In addition to urchins, corals, and sharks, the scientists found a lot of one thing: trash.

"Every single trawl had trash in it," said Meg Burke, California Academy's director of teacher and youth education. "Plastic, parts of plastic bags, bottles, even dirty diapers—things like that. So the impact of humans on the marine ecosystem was blatantly clear."

New Sea Slug

Photograph courtesy Terry Gosliner, California Academy of Sciences

This new species of colorful nudibranch, or sea slug, was found during the Philippines expedition. Nudibranchs are technically mollusks, but unlike clams or snails, sea slugs rely on powerful toxins and bright colors to warn away predators.

Though this species doesn't yet have a scientific name, the visually striking invertebrates are easy to tell apart, scientists say.

"You can identify different ones like you identify different people," expedition leader Gosliner said.

Pink Coral Colony

This pink coral colony, found recently in the Philippines, may represent a new species because it grows differently than related corals.

But confirmation via microscopic analysis, DNA sequencing, and taxonomic description may take some time, if only because some of the team's specimens need to be specially shipped back to the U.S. from the Philippines.

New Nudibranch

Photograph courtesy Terry Gosliner, California Academy of Sciences

The Philippines expedition discovered at least 50 new species of nudibranch, including this one in the Armina genus.

Worldwide, there are more than 3,000 known species of nudibranch making their homes at almost any depth. The area surrounding Luzon is renowned for its nudibranch diversity, with more than 800 species known.

This makes the discovery of 50 new species even more remarkable, Burke said— especially because expedition leader Gosliner, a nudibranch expert, has been diving around Luzon since 1992.

"It's a really good indication of the amazing biodiversity in the Philippines," Burke said.

Pea Urchin

Photograph courtesy Terry Gosliner, California Academy of Sciences

Two views show the test, or shell, of a likely new species of pea urchin found in shallow water surrounding Luzon. Pea urchins, some of the smallest urchins, eat particles of organic material found in sand.

The team snorkeled and dived through reefs around the island, carefully collecting everything from urchins to sea pens to giant sea worms.

In the Bag

Expedition leader Gosliner holds up another new nudibranch species collected in the Philippines' Verde Island Passage.

The Philippines are home to 800 species of nudibranchs, of which 400 have yet to be formally named.

Some of the newly discovered species had eluded scientists because they're so tiny, reaching just a few millimeters in length. But the team also found some "pretty good size" nudibranchs—like the species shown here—illustrating that reefs are "just such incredibly complicated ecosystems," Burke said.

Sea Pen of the Night

Photograph courtesy Gary Williams, California Academy of Sciences

Only emerging at night, this new species of sea pen went undiscovered until the recent Philippines expedition.

Like corals, sea pens are actually composed of colonies of polyps—tiny animals—working together. The bottom polyp in a sea pen becomes the base after shedding its tentacles and growing a large "bulb" to anchor itself in the sandy sea bottom.

Sea "Pancake"

Resembling a colorful pancake, this new nudibranch looks ready for a bizarre brunch.

The expedition brought together more than two dozen scientists from the Philippines and more than 30 from the California Academy.

The goal was to catalogue the country's species richness "and ensure that this remarkable biodiversity is afforded the best possible chance of survival," expedition leader Gosliner said in a statement.

New Wonderworm?

A new worm from the genus Myrianida was discovered amongst coral rubble during the Philippines expedition. Myrianida worms are small—generally less than 3.9 inches (10 centimeters) long—segmented, and often brightly colored.

They also are part of a family, the syllids, that has a very complex and strange reproduction style, said zoologist Kristian Fauchald, of the Smithsonian's National Museum of Natural History, who was not involved in the expedition.

This specific worm will "bud" asexually, creating a second generation of worms that will reproduce sexually. That second generation will then grow into more worms like this one. Myrianida is one of the lesser-known genera of the syllid family, making this new worm a possible key to unlocking the secrets of the genus.

Shark Inspection

Photograph by Andy Isaacson

California Academy of Sciences fish scientist John McCosker inspects the trawl-caught swell shark, which is likely new to science. Besides the shark, the team found very few relatively large fish, especially in the shallow-water dives, Burke noted.

"The Philippines have suffered from some very unsustainable [fish] harvesting practices, including dynamite and cyanide," she said. Only recently are fish of "decent" size returning to these waters.